[R] Extracting "row.names"

Richard Pearson richard.pearson at postgrad.manchester.ac.uk
Mon Jun 23 21:50:02 CEST 2008


As a further aside, names is also not the best choice for a variable name for the same reason.

Richard.


Erik Iverson wrote:
> row.names is a function that takes a data.frame as an argument.  So how 
> about
> 
>  > row.names(data)
> 
> ?
> 
> As an aside, 'data' is not the best choice for a variable name in R, 
> since there is a function called 'data' that will get overridden if you 
> do this ...
> 
> Patrick Richardson wrote:
>> List,
>>
>> I'm trying to extract the row names of a table I have read into R.
>>
>>> data <- read.table("mesodata.txt", header=TRUE, row.names=1)
>>
>> When I try to extract them using,
>>
>>> names <- data$row.names
>>
>> I get,
>>
>>> names
>> NULL
>>
>> I've tried changing to a matrix, data frame, etc. and still get 
>> "NULL". I've checked ?row.names as well as help on extracting part of 
>> an object,
>> etc. and unless I'm missing something obvious (likely), I can't figure 
>> out
>> how to extract them.
>>
>> BACKGROUND
>> I want to extract the row names (which are basically gene id's) as 
>> well as
>> some other columns (which I can do successfully) and "cbind" them into
>> another data frame (which I can also do successfully). I just can't 
>> get the
>> row names extracted (Assigned) to an seperate object.
>>
>> Any suggestions would be appreciated.
>>
>> Many Thanks,
>>
>> Patrick
>>
>>
>>
>>> sessionInfo()
>> R version 2.7.0 (2008-04-22) i386-pc-mingw32
>> locale:
>> LC_COLLATE=English_United States.1252;LC_CTYPE=English_United
>> States.1252;LC_MONETARY=English_United
>> States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252
>>
>> attached base packages:
>> [1] stats     graphics  grDevices utils     datasets  methods   base
> 
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-- 
Richard D. Pearson             richard.pearson at postgrad.manchester.ac.uk
School of Computer Science,    http://www.cs.man.ac.uk/~pearsonr
University of Manchester,      Tel: +44 161 275 6178
Oxford Road,                   Mob: +44 7971 221181
Manchester M13 9PL, UK.        Fax: +44 161 275 6204



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